Electrical arc barrier



April 29, 1941. E ow 2,240,007

ELECTRICAL ARC BARRIER Filtd July 29, 1939 3 Sheets-Sheet 2 i Mad (fa/7 z'nsu/afz'ny and I NVENT OR. Mafia/:25. FUWER ATTORNEYS.

April 29, 1941. L. E. POWER 2,240,007

ELECTRICAL ARC BARRIER Filed July 29, 1939 3 Sheets-Sheet 3 111v? fl zz J6 I INVENTOR. LA [IRE/V55 E. PHWEH ATTORNEYS.

Ants- Patented Apr. 29, 1941 sea 6W EIECTBICAL ABC BARRIER Laurence E. Power, Milwaukee, Wis asaignor to Dostone Corporation, La Fayette, Ind., a corporation of Indiana Application Jill! 29, 1939, Serial No. 287,351

Claim.

It is a still further and particular object of this invention to provide for an arc chamber that is highly resistant to the destructive action of an electrical arc and which are chamber may be made to conform to the required shape with accinacy.

This invention is a discovery that the material of the type known as Rostone," which material is used for the exterior walls of houses or other like structures, has particular properties that make this material especially useful as an arc barrier in the form of an arc chamber or arc hood.

My invention is the discovery that the material Rostone has high dielectric strength, does not feed an electrical arc, exhibits a marked resistance to the destructive action of an electrical arc, and may be molded or formed to a required shape with a high degree of accuracy.

This material Rostone" can further be adapted for use as an electrical arc barrier in that it can be made moisture resistant by proper impregnating treatment.

Heretofore, difllculty had been experienced in the production of a satisfactory electrical arc barrier in the form of an arc chamber, which was accurate in the various required dimensions.

This problem become accentuated in arc chambers where accurate spacing of contacts and terminals was required and in arc chambers where the parts of the chamber had to fit together with only a small tolerance of dimensions allowed.

My invention provides for the accomplishment of the above named objects, and in the accompanying drawings I have shown two forms of arc hood structures in which this material "Rostone" has proven itself particularly useful.

Figures 1, 2 and 3 are drawings of a structure composed of three sections and which structure forms an enclosure for the switch contacts and also provides a mounting for the switch contacts and necessary terminals.

Figures 4, 5 and 6 are drawings of another type of structure which is a single molding and which structure forms a chamber for the switch contacts and also provides a mounting for the switch contacts and necessary terminals.

Figure 1 is a front elevation of the arc hood assembly showing by means of a partial section the stationary and movable contacts in their normally open position.

Figure 2 is a side elevation of the arc hood assembly showing by means of a partial section along the line 2-2 in Figure 1 the interfltting of the hood structure and the stationary and movable contacts in their normally open position.

Figure 3 is an exploded perspective view of the are hood showing the three component parts of the arc hood and the stationary contact assemblies.

Figure 4 is a iront elevation of the other type of arc hood assembly and showing by means of a partial section the stationary and movable contests in the normally open position.

Figure 5 is a side elevation of the are hood of Figure 4 showing by means 01! a partial section along the line 5-5 in Figure 4 the stationary and movable contacts in their normally open position.

Figure 6 is a perspective view of the arc hood without terminals, contacts or any mounting parts showing the character of recesses and proiections for the mounting of such parts.

The are hood assembly I shown in Figures 1, 2 and 3 consists of a back section 2 that is mounted to the mounting plate 5 by means of mounting screw 6 and hood locking bolts 1-1, a top section 4 having mounted therein stationary contact assemblies 8, an actuator l, and movable contact assemblies ill, and a front section 3. The three sections of the arc hood are held together by the interfltting of the three parts as shown in the drawings and by the hood locking bolts 1- The chamber designated as ll for each set of stationary and movable contacts. I and II respectively, is formed by the interior walls of sections 2, 3 and I and as shown are in accurate relationship to the position 0! the said movable and stationary contacts.

This type of arc hood assembly may be used on switches for multi-phase motors oi the higher horsepowers ranging from the neghborhood of fifteen horsepower on upwards and arcs of high intensity may occur in the individual chambers on the operation of the switch contacts.

This type of arc hood structure requires acsurfaces of the parts in that the confined are or the gas of the confined arc cannot easily escape between such engaging surfaces.

The material Rostone". ansers the requirement of good fit and further is highly resistant to the action of the are which as mentioned before occurs within the chamber.

Referring to Figures 4, 5 and 6 the hood designated by numeral Ii is secured to a support bracket l2 projecting from a mounting plate The top portion of the hood has mounted therein the stationary contact and terminal assemblies i4 and il. An actuator :4-= generally by the numeral II carries. through interposed springs 22, the movable contact assemblies I! which are adapted to engage the stationary contacts of assemblies M and II. The chamber for each set of movable and stationary contacts is designated by the numeral ll.

It is to be noted that recesses designated as and II for the front and back contact assemblies i4 and I5 respectively, are of necessity accurately formed in that the engaging portions of the contact assemblies may at all times be in alignment.

Itisalsotobenotedthatthewallsofthe chamber II for each set of contacts are closely adjacent to the contacts and herein accuracy is again of great importance.

Thearchoodasshowninl'igures4,5and6is adapted to be used for switches for industrial motors of the lower horsepowers as compared to the motors controlled by the structure shown in Figures l, 2 and 3.

The material Rostone is composed of finely divided alkaline earth materials of the group including lime and magnesia; finely divided hydrated aluminosilicic acid such as clay, shale or slate; eral filler such bestos is 14mand water sufilcient complete the esired reaction during the indurating process.

The preparation of this material which is known as Rostone" is given in U. 8. Patent No. 1,852,672 issued April 5, 1932, to Harry 0. Peifer et al, U. 8. Patent No. 1,877,960 issued September 20, 1932, to Harry 0. Pefier et al, and U. 8. Patent No. 1,942,770 issued January 9, 1934, to Harry C. Peifer et al. These patents clearly disclose the procedure and technique of preparing the material which is the subject of this patent.

As pointed out in the above patents, the raw materials used in formulating this material are all obtainable in large quantities of uniform quality and at comparatively low cost. The preparation of the molding material, its formation by pressing and indurating are all simple and inexpensive operations. It is possible with this molding material to obtain far superior detail and accuracy of molded parts than heretofore obtainable from materials having equivalent arc resisting characteristics and the time of particularly the indurating period, is materially shorter than with other equivalent materials.

Those experienced in the art of designing and manufacturing arc barriers and are enclosures, as herein disclosed, will readily appreciate the value of a material that can be satisfactorily and economically used to manufacture both simple and complicated arc barrier structures of superior q ity.

What I claim as my invention is:

1. An electrical insulating and ar g element that unwitting-mew:- structive action of an e ectric are including an indurated mixture of finely divided hydrated aluminosilicic acid earth materia.

elec rical insulating and arc-resisting element that exhibits marked resistance to destructive action of an electric arc including an indurated mixture of finely divided hydrated aluminosilicic acid, finely divided alkaline earth base material, water W 3. An electric swi device including an electrical insulating and arc-resisting element subject to contact of an electric arc wherein said insulating material is composed entirely or in part of an indurated mixture of finely divided hydrated aluminosilicic acid and finely divided alkaline earth base material.

4. An electrical arc chamber formed from an insulating and arc-resisting 'indurated mixture of finely divided hydrated aluminosilicic acid and finely divided alkaline earth base material.

5. An electrical arc chamber formed by the fitting together of at least two separate insulating members wherein one or more of said matlating members include as an essential part an insulating and arc-resisting indurated mixture 'of finely divided aluminosilicic acid and finely divided alkaline earth base material.

8. An enclosure forming a chamber for a movable and stationary switch contact. said enclosure including complementary sections, the interior faces of said sections being exposed to the arc incidental to the operation of said switch contacts, and said sections including as an essential part thereof an insulating and arc-resisting indurated mixture of finely divided hydrated aluminosilicic acid and finely divided alkaline earth base material.

7. An electric switching device to interrupt electric currents encountered in industrial electric motor control, comprising spaced stationary contacts and a complementary bridging contact member for such currents, in combination with a stationary contact-mounting means and are enclosure having a surface which may be engaged by the are formed on the opening of said contacts and which includes a portion lying between said stationary contacts, said contactmounting means and are enclosure comprising an insulating and arc-resisting indurated mixture of finely divided hydrated aluminosilicic acid and finely divided alkaline earth base material.

8. An electric switching device, comprising in combination two spaced stationary contacts, a bridging contact therefor, and an arc-enclosure and stationary-contact-mounting means for said contact structure composed essentially of an insulating and arc-resisting indurated mixture of finely divided hydrated aluminosilicic acid and finely divided alkaline earth base material.

9. An electric switching device to interrupt electric currents encountered in industrial electric control, comprising a stationary contact and a co-operating movable contact, in combination with a common means for mounting said stationary contact and for confining arcs incidental to the opening of said contacts, which means is composed essentially of an insulating and areresisting indurated mixture of finely divided hydrated aluminosilicic acid and finely divided alkaline earth base material.

10. An electric switching device adapted to safely interrupt electric currents of high intensity encountered in industrial electric control, comprising, in combination with switching contacts for establishing and interrupting such currents, a contact enclosure comprising an insulating and arc-resisting indurated mixture of finely divided hydrated alumlnosilicic acid and finely divided earth base material.

LAURENCE E. POWER.

CERTIFICATE OF CORRECTION. Patent No. 2,2ho,oo7. April 29, 19in.

mumca E. POWR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 13.0, for the word "become" read --.became; page first column, line 8, for "ansers" read -answers-; page 5, second column, line 5, claim 10, after "divided" insert --alkaline--; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of ma A. D. 19m.

Henry Van Arsdale, (Seal) Acting Commis sioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,.2ho,007. April 29, 191 1.

LAURENCE E. POWER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 1 0, for the word "become" read +became; page first column, line 8, for "ansers" read -ansWers-; page 5, second column, line 5, claim 10, after "divided" insert alkaline-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the c ase in the Patent Office.

Signed and sealed this 27th day of May, D. 19L 1.

Henry Van Arsdale, (Seal) Acting Commie sioner of Patents. 

